5 stars: This game is fun & challenging and level 14 & 15 were difficult on normal & hell, but they weren't game enders. I'm on level 39 and I haven't paid anything yet. I watch the ads and I've been considering buying a hero, but money isn't needed to play. There's a lot in this game, including tournaments and weapon smithing, to upgrade and play with. I'm happy with it. (:
4 stars: The game is great, I enjoy it, and the ads are not invasive, but there is a very annoying bug... In the tournament supposed to be 100 levels. I got to 25 and the game just stops. If I get out of the mode, then I lose the progress. It is very annoying as I spent a lot of time on it. Also, it is not clear where and how to contact support if there is any.
2 stars: Pay-To-Win: Name of this game is simple. If you want to make it past the first few levels, open your wallet. It is a well put together game with great design and mechanic choices. It's too bad it is impossible to get past level 14 without buying your victory. This is a fun way to pass a few hours, but you will quickly delete it unless you're willing to buy your way past the very apparent pay-wall.
2 stars: Starts out pretty fun but the difficulty scales up ridiculously quite quickly as a clear play to push players into microtransactions to progress without extensive grinding of earlier levels to eke out a tiny bit of progress after days or weeks of playing the same missions repeatedly and constantly bombarding you with pop-ups ...